That and they market the hell out of the car, cutting out middle men where possible. The aren't burdened by the dealership model and have been very protective of their brand. It's not like electric cars weren't made by the large auto makers, they just weren't willing to spend as much as Tesla has to feet to profitability. When Toyota made the Prius they went all in, now the Prius tech is in many of they're other cars. American manufacturers doubled down on bigger, higher polluting trucks and SUVs that all look the same and haven't had innovation in years.